Sound-box for talking-machines.



Ubll SS FA WILIBURN N. DENNISON, OE MERCHANTVILLE, NEW JERSEY, ASSIG'NORTO VICTOR TALKING MACHINE COMPANY,.A CORPORATION 0F NEW JERSEY.

SOUND-Box ron 'rAILKINGr-ivneosiiuiis."v

To all whom 'it may concern Be it known that I, WILBURN N. DENNL son, acitizen of the United States, and a resident of the borough ofMerchantville,

county of Camden, and State of New Jersey,

box to improve the reproduction of sound therefrom; to provide a soundbox in which the diaphragm will be normally held fiexed by an initialpressure when not in operation to counterbalance the pressure which isordinarily exerted on the diaphragm by the lateral pressure on thestylus due to the propelling action of therecoid upon one side of thestylus, in carrying the sound box. across the face of the record.; tomake it possible to assemble commercially large' numbers of sound boxeswith diaph'ragrns held between gaskets with substantially the sainepressure; and to provide other iniprovements as will appear hereinafter.

In the accompanying drawings, Figure 1 is a front elevation of a soundbox constructed in accordance with this invention; Fig. 2 a longitudinalvertical section of the same; Fig. 3 a bottom plan view of the same witha, part shown in dotted lines for clearness; Figs. l and 5 arelongitudinal sectional views of details of the same; Fig. 6 is afragmentary transverse section of a detail of the saine; Fig. 7 afragmentary side elevation partly in section of a portion of the same;Fig. v8 a horizontal section on line 8, 8 of Fig. 2; and Fig. Sanlenlarged longitudinal section of a portion of the same.

Referring to the drawings, one embodi-v ment of this invention comprisesan outer casing l, a diaphragm 2, gaskets 3 and 4:' for holding thediaphragm in position, an annular back plate 5 which is. provided withSpecification of Letters Iatent.'

Patented aan'. es, ieie.

. Appiicaaon'iiied May 27, 1909'. -serial No. 498,697.

means for securing a gasket in place, and also with means for connectingthe sound box .to the usualv sound conducting tube, a locking .ring forretaining the back. plate in position in the outer casing, and a stylusbar 7 mounted to oscillate upon the casing, the front of the casingbeing recessed as at to permit of the free oscillation of the ar. i

The locking ring 6 has a substantially fiat inner surface, and the backplate 5 diers from the ordinary` construction in that itis provided uponits outer face with a circular marginal rib 5 curved in cross sectionand Ahaving a convex outer side against which the fiat inner surface `ofthe locking ring 6 engages throughout only a very narrow region which ispractically only a circular line. This construction makes it easy inpractice to insure a substantially uniform pressure of the locking ringagainst the back plate'5 without having to provide carefully fittedcoperating surfaces between the ring and the back plate and aHords asimple arrangement whereby the seating of the back plate in the outercasing 1 may be effected with certainty.

The outer casing l of the sound box coinprises a substantiallycylindrical rim portion 8, having an inwardly extending lange 9,integral therewith upon the front side thereof, forming a circular frontwall having a centrally arranged opening 10. On the interior face of thewall 9, and spaced from the internal periphery of the outer casing is anannular rib or projection 11 concentric with the wall 9. This rib formswith the internal surface of the rim 8 and the internal surface of thefront wall of the casing, an annular groove 12, substantiallyvrectangular in cross section but with rounded.

bottoni corners, the walls of whichy form a seat for the outer gasket 3.

' The rim 8 of the casing lis counterbored from its rear end forming acylindrical recess coaxial therewith to receive the back plate 5, andforming a rearwardly facing annular stop shoulder 13 to limit the inwardmovement'of the back plate. The back plate 5 forms the rear wall of thesound box casingi and is substantially parallel to and coaxial with thefront wall 9 of the casing.

The back plate 5 is preferably madeof the same material as the outercasing and is provided atits periphery with an inwardly projectingcylindrical Harige 14, which abuts against the internal stop shoulder 13of the rim 8 and limits the inward movement of the back plate.` Thisback plate 1s also provided, with an annular rib or projection 15 y onits inner face similar to and coaxial with 16 similar in shape and equalin size to the opposite groover12, and the walls of which forni a seatfor the inner gasket 4.

For increasing the eiliciency of the sound box the back plate isprovided with-a rib projecting inwardly toward the diaphragm, and may beformed as a cylindrical annular bushing 17 of .metal or other suita'blematerial threaded into or otherwise adjustably secured in the centrallydisposed circular' opening 18 of the back place, the inner portion ofthe bushing projecting inwardly from the adjacent internal surface ofthe back plate and forms a rib or projectionwl terminating in Very closeproximity to lthe diaphragm, the space between the end of the rj v saidrib 17 and the diaphragm being substantially as small as is practicalwithout causing actual contact between the said rib and the diaphragmwhen the sound box is in operation. The bushing is provided in its outerend. with apertures 17 adapted to receive a spanner wrench whereby thebushing 17 may be adjusted toward or awav from the diaphragm. Ifpreferred this bushing 17 and the-annular projection 17v may be madeintegral with the back plate, and in any case forms a continuous`projection bordering or surrounding the opening in the back plate andthe internal or lcylindrical surfacego'f` the bushing 17 forms-theinternal wall df'the inner end of the sound conducting opening 18 of thesound box casing.

AThis construction of the back plate and bushing leaves an annularrecess or chamber 18 inthe inner rear face of the casing concentric withthe outlet so that the passage of air orsound waves into the outletor'passage from the interior portionof the casing surrounding the outletand in the rear'- ot the diaphragm, is restricted by the inwardlyextending bushing or rib 17 at the margin of the said outlet or'passage,and when the diaphragm vibrates toward the outlet, part'v of.

the air in the sound box will be partially trapped by the diaphragm .inthis recess or chamber 18 and compressed to a greater extent than would`he the case if the passage of air through the outlet were not thus re-4stricted. This compressing of the air inthe recess or chamber 18 mayalso serye to cushion the dlaphragm and some of the air thus-'compressed will be sharply forced Vthrough `through the outlet to thesound' conveying tube or opening is restricted, the central circularportion of the diaphragm bounded by the said annular projection is freetoset up vibrations directly in a. straight li-ne through the opening inthe back ofthe sound box to the sound conveying tube and the characterof the sound waves may thus be largelydetermined by the action of thiscentral portion of the diaphragm as well as by the action of the airejected into the said outlet from the recess or chamber 18.- Thisconstruction gives a reproduction having an unusually clear and definitequality.

, F or attaching the sound box to the usual sound conveying tube 20, theback plate fof the box is provided with a coaxial rearwardlyprojectingtubular extension 19 conimunicating with the sound conducting opening 18and adapted to receive the end of the sound conducting tube 20. Theinternal diameter of this tubular extension is preferably about tliesame diameter as the external diameter of the bushing 17 in the backplate,

in the rim 8 of the outer casing of the sound box, a locking ring 6,screw threaded on 'its external periphery, as shown at 23, is'

threaded into the rear ofthe outer casing, the outercasing'beingprovided with internal screw threads 24 to receive theexternal threads of the ring. The locking ring 6 is provided withSpanner holes 25 to receive a spanner wrench for rotating the ring totighten the same against the back plate 5, and to force the back plateagainst its seat.

The two gaskets 3 and 4, for supporting j the diaphragm, are preferablymade of'rubber, o r o-ther'yielding material, and are each i in the formof a solid ring having a body portlon substantially rectangular in crosssection but having its corners slightly rounded as atf26. Each of thesegaskets is provided Vupon one of its side faces with" an annular riborcontinuous projection 27 coaxial therewith which tapers outwardly incross section from the body of the gasket and terminates in a narrowflat face parallel to the ilat sides of the gasket. The sides or 5peripheral edges of the rib are preferably concave and curved in crosssection and tangential to the adjacent sideof the body ot the gasket. c

The gaskets are positioned upon their y seats in the casing asheretofore described,

,20 inserted within the outer casing, with its flange 14 abutting'against the shoulder 18 of the outer casing, the diaphragm will be heldyieldingly in position between and by the ribs of the gaskets. The flatoutside face of each gasket resting in the seat, forms a lirm supportfor the gasket and prevents its displacement and the gasket ispreferably oblong in cross section and of greater width than thickness,as shown in Fig. 6, to form a relatively broad supporting surface forthe gasket.

The thickness of the gaskets 3 and 4l and the depth of the recesses orgrooves 12 and 16, in the casing 1 and backing plate 6 re spectively, ismade so that when the back plate 5 is screwed down hard upon theinternal stop shoulder 13 of the casing, the diaphragm will be heldbetween the ribs of the gaskets 3 and 4 with the requisite and de- 4osired pressure so that with uniform gasket-s and with a number of soundboxes provided with groot/'es of the same depth, and the shoulder 13 inthe same position with respect to the grooves 12 and 16, a large numberof sound boxes can be assembled substantially absolutely alike b ymerely pressing the back plate 5 up firmly against its shoulder by thelocking ring 6. v

The diaphragm -or vibratory member for compressing sound waves ispreferably made of mica o-r any other suitable resilient material of theusual circula-r form. The diaphragm is arranged coaXially with the-casing and is somewhat less in diameter than the internal dia-meter ofthe outer casing so that the periphery of the diaphragm is spaced fromthe casing.

The stylus bar or diaphragm actuating device, comprises an arm 28, anoii'set or laterally extending portion 29, and a stylus holder 30. Thestylus holder 30 is'provided with the usual stylus socket vitor holdinga stylus 31 and with a thumb screw 32 for retaining the stylus inposition. The arm :28 of lthe stylus bar is tubular and is connected atits inner end to the'central portion of the diaphragm by any suitablemeans. The inner end of this arm spreterably substantially circular incross section and extendsoutwardly substantially perpendicular to thediaphragm, and then curves to meet the main portion 34 of the arm whichvextends in a direction substantially parallel to the diaphragm. Thismain portion S4 of thev arm flares outwardly from its junction with theinner end of the arm and is substantially elliptical in cross section,the longer axis of a cross section of the main portion l-l beingsubstantially at right angles to the diaphragm, when the diaphragm isflat. so

The oil-set or laterally projecting portion 29 of the stylus barconnects the stylus holder 30 and the arm 2S of the bar, and Jisyieldingly connected to a supporting member 35, which is rigidlyattached to the 85. sound box casing, as will be described hereinafter.

The supporting member comprisesa main or body portion consisting of twosubstantially rectangular flat rigid plates 37 90 and 38,.and the majoror central portion of a thin flat plate 89 of tempered spring steel orother resilient or yielding material which is clamped between the rigidplates 37 and 3S by means of rivets 40 extending through 95 all theplates and securing them permanently together. The yielding plate 39 isprovided with spaced yielding arms 41 and a2 integral therewith whichproject foryvardly from its main portion and from the front edges of theplates 37 and 38, as shown partly in dotted outline in `llig. 3.

The outer casing A1 is provided upon its under surface with 'a boss orliXed support 43 having an outer plane surface 44 sub- .10o stantiallyrectangular in shape against which is rigidly secured the supportingmember 35 by :means of screws l5 passing through the supporting memberand into the boss. The plane surface of the boss is of ll@ substantiallythe same shape and dimensions as the inner surface of the supportingmember and is recessed to-receive the heads of the rivets of thesupporting member. The supporting member thus bears against the H5 bossthroughout substantially the entire eX- tent of the supporting member,thus insur- 'ing avery rigid connection between the supporting memberand the sound box, and obviating the slight vibration which might ariseif the body or main portion of the supporting member projected to anygreat eX- tent` beyond the edge of theboss.

' vThe off-set portion'? of the stylus bauis composed of lthreethicknesses of platesll, :W5

a7 and e8. .Ot these the two plates 46 and 47 are or thesame size andform and each has a pair of laterally progecting arms 46 and 47extending in opposite directions respectively from the stylus har,Between the la@ free ends of these arms .are secured the free ends ofthe projecting resilient arms 41 and 42 of the steel plate 39, by meansof rivets 40', thus forming spaced yielding resilient supports for thestylus bar. These two plates 46 and 47 are spaced apart by the thirdplate 48 whichis of the rsame thickness as the spring arms. Thesupporting member 35 is recessed centrally on its front edge as at 49 toreceive the inwardly projecting central portion 49 of theoff-set portion290i? the stylus bar, and the front surfaceof the .stylus holder isrigidly secured by riveting or otherwise, in van aperture extendingthrough the three plates, 46, 47 and 48 in the inwardly projectingportion 49 of the off-set portion of the stylus bar.

The stylus bar is preferably positioned upon the sound box so that theaxis of oscillation of the bar and the longitudinal axis of the stylussocket are substantially in the plane of the diaphragm, 'when the diaHphragm is in a flat condition, and the longitudinal axis of thestylussocket is preferably arranged radially of the sound box. The spacebetween the offset portion of the stylus bar and the adjacent edges ofthe supporting member 35, is preferably onlysufficiently wide to permitof the free oscillation of the stylus bar and the bar is thus restrainedto oscillate upon a substantially fixed axis.

vFor connecting Vthe outer end of the arm Q8 of the stylus bar with theoff-set portion Q9 of the bar, the front portion of the off-set portion29 is provided with an aperture 50 extending through the plates 46, 47and 48 into which tightly fits the elliptical outer end of the arm. Acomparatively short transversely elliptical tube or bushing 51 of softannealed brass or other suitable material having its external dimensionssubstantially the same as the corresponding internal diameter of theouter end of the arm 28, and having its inner end slightly tapered, is

then forced tightly into the end of the arm,

slightly expanding the arm and compressing the tube and rigidly bindingthe end of the varm in position in the aperture 50;

Vhile the outer end of the arm 28 and the aperture 50 in the off-setportion Q9 are shown as elliptical. other shapes mightbe employedwithout departing from the spirit of this invention. The bushingv 51 mayalso be of difierentshape from that illustrated,

so long as it corresponds to the shapev of the internal diameter of theouter end of the,

arm 2S, so that when forced into said arm,

it effects a rigid binding of the said arm supporting the sound box thebar will be slightly turned or displaced on its axis from its normalposition, slightly flexing or applying aninitial tension to the spacedspring arms supporting the stylus bar, and the upper end of the stylusbar will co11se p1e11tl y exert a slight initial pressure rearwardlyagainst the central portion of the Adiaphragm, springing or flexing ordishing the diaphragm which is preferably made of mica or otherresilient material, slightly in ay direction toward the outlet in theback plate of the'sound box casing, as shown exaggerated in Fig. 2.

When the sound box, thus constructed. is supported by its stylus upon asound record in a siate of rest or in an inoperative position. thediaphragm will remain in substantially the same flexed condition as whenthe sound box is not supported by the stylus, but being perhaps slightlymore flexed, due to the. weight of the sound box on the free end of thestylus, which vhas a slight tendency to turn the stylus bar about itsaxis and to increase correspomlingly the tension upon the spaced springarms supporting the bar and the pressure of the upper end of the stylusbar against;J the diaphragm. lVhen,

however, the sound box is in operation and 1s being propelled. as iscustomary, across.

a record by the engagement of its stylus with the record. a pressuresufficient to cause the travel of the sound box will lbe exerted uponthe stylus bar in the direction of the travel of the sound box, asindicated by the arrow in Fig. 2, tending to turn the innerend of thestylus bar outwardly and to relieve the initial inward pressure upon thediaphragm.

The initial pressure or tension upon the diaphragm is adjusted to malteit substanw tially balance the pressure exerted upon the side of thestylus during the operation of the sound box. to propel the sound boxacross the record, so that act-ing through the stylus bar, the turningmoment of one of these pressures will counterbalance the other and thediaphragm will be under substantially no tension or pressure due to thepropulsion of the sound box. when in operation, across the record, andwill be substantially free, as far as these forces are'conce1-ned, toassume its natural form, which in this case would be thatof a flat disk.By

lll

this construction a symmetrical action of the applied also to otherforms than the one illustrated, for instance the sound box might be ofthe type known as pneumatic, in which a current of air or other fluid isforced through the sound box and the sound Waves are impressed upon thefluid current by a. vibratory flat, flexible resilient valve or othervibratory means actuated by a stylus bar. In this case the valve orother vibratory means would then take the place of the diaphragm of thesound box illustrated, and when the term diaphragm is used in the claimsit is intended to cover any such valve or vibratory means equivalent toa diaphragm for performing thesame function of impressing sound Waves.

Although only one form of this invention has been illustrated anddescribed, the invention is not limited to the exact construction setforth, as various changes might be made in'applying this invention,Without departing from the spirit of the invention or the scope of theappended claims.

` Having thus fully described my invention, I claim and desire toprotect by Letters Patent of the United States:

l. A stylus bar having a member provided with an aperture, a tubular armtting in said aperture, and means Within said tubular arm for holdingthe same in position.

2. A stylus bar having a member provided with an aperture, a tubular armfitting in said aperture and tubular means iitted tightly Within saidtubular arm for holding the same in position.

3. A stylus bar having a member provided with an elliptical aperture, anarm ellipitical in transverse section litting tightly in said apertureand an elli )tical tubular bushing fitted tightly into sai arm to holdsaid arm .and said member rigidly' together.

4. A stylus bar having a member provided with an aperture, a tubular armfitted tightly in said member' and a bushing fitted tightly in said armto hold said arm and said member rigidly together, said arm taperingaivay from said member and saidbushing having its inner end tapered.

copies af una patent may ae @baisee fm A gasket for supporting adiaphragm in a sound box comprising a yielding member substantiallyrectangular in transverse section and having an annular rib projectingtherefrom.

6. A gasket for supporting a diaphragm in a sound box, `comprising asolid yielding member substantially rectangular in transverse sectionand having an annular rib -projecting therefrom.

7. A gasket for supporting a diaphragm in a sound box comprising ayielding ring lsubstantially rectangular and oblong in transversesection and an annular jecting from one side thereof.

8. A gasket for supporting a diaphragm in a sound box comprising ayielding ring substantially rectangular in transverse section and havingrounded corners, and an rib proannular rib projecting from one sidethereoi 9. In a sound box, the combination with a diaphragm, of anannular yielding gasket having an annular rib projecting therefrom, saidrib having a flattenedface in contact with the diaphragm.

10. In a sound box, the combination of a casing, a bach plate having acircular rib of curved cross section extending from the back thereof,and a nut, threaded in said casing and seated upon said rib.

1l. ln a sound box, the combination with a. substantially cylindricalcasing, of a substantially circular back plate telescoping in saidcasing, and an annular member engaging said casing and contacting withsaid back plate only in a substantially circular line, and clamping saidcasing and said back plate in relatively xed relation.

l2. ln a sound box, the combination with a substantially .cylindricaleasing, of a substantially circular plate telescoping in said casing,and annular means carried by and rotatable coaxiallj7 with respect tosaid casing and engaging said plate only in a subA stantially circularline and clamping said plate in a fixed position with respect to saidcasing.

ln Witness whereof l have hereunto set my hand this 26th day of May, A.'l). 1909.

W'LBUBN N. DENNSN.

Witnesses:

FRANK B. ltronLnToN, Jr., Hanni' E. YV. KENNEDY.

tivo cents each, 'by sreasng the Gommssioner of Patents, Washington, n.e.

